Steam producer with radiation flue



Dec. 26, 1967 Zl 3,359,948

STEAM PRODUCER WITH RADIATION FLUE I Filed Dec. 21, 1965 3 Sheets-Sheet1 1967 K. KNlZIA 1 r 3,359,948

STEAM PRODUCER WITH RADIATION FLUE 3 Sheets-Sheet 2 Filed Dec. 21, 1965FIG. 20

FIG. 2

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STEAM PRODUCER WITH RADIATION FLUE Filed Dec. 21, 1965 s Sheets-Sheet sUnited States Patent 3,359,948 STEAM PRODUCER WITH RADIATION FLUE KlausKnizia, Gummersbach, Germany, assignor to L. & C. Steinmuller G.m.b.H.,Gummersbach, Germany Filed Dec. 21, 1965, Ser. No. 515,370 Claimspriority, application Germany, Dec. 24, 1964, St 23,137 Claims. (Cl.122-235) The present invention concerns a steam producer with a verticalfire-box and with a vertical flue connected to the top portion of saidfire-box.

It is known that return ceilings or walls directed toward the combustionchamber proper favorably aifect the combustion, reduce the combustiontime and intermix the flue gases so that also the temperaturedistribution over the entire cross section of the radiation flue will beequalized. These return walls or the like are employed with boilershaving front firing boxes and also with boilers having corner firingboxes.

With boilers having oppositely located burners (boxer arrangement), itis not possible for geometric reasons to draw the respective wallsopposite the burners inwardly toward the fire-box to any materialextent. Consequently, the flue gases in the center path have aconsiderably higher temperature than the flue gases adjacent the wall.This fact is particularly unfavorable when the flue equipped withcontact heating surfaces follows the radiation flue without any materialchange in the direction of flow of the flue gases.

Similar conditions prevail with steam producers having cornerfire-boxes. Attempts have been made to obtain an equalization of thetemperature over the entire cross section by arranging hairpin-shapedtubes (twist impeders or rectifiers) which from opposite sides extendinto the firebox and interengage each other in a comb-like manner. Theseinserts, however, have an effect which is precisely contrary to thataimed at by the present invention.

It is also known in connection with melting chamber boilers which arefired from two oppositely located sides to produce a turbulence in themelting chamber by arranging a displacement body in the central planethereof. Such displacement body is in the form of a horizontal bodyhaving the shape of an isosceles triangle in cross section with its baseat the bottom. The body is in the fire box above the burners andconstricts the fire-box toward the sides above the burners and therebyseparates from the main firing chamber two post-burning chambers inwhich the fire gases subjected to turbulence by the constrictions formedby the body will burn faster. With regard to the radiation flue, thepost-burning chambers are, as customary,.separated by slag interceptinggrates positioned at the upper ends of the post-burning chambers.

According to another heretofore made suggestion, a displacement body issuspended in the fire-box between opposed burners and at about the levelof the burners. This displacement body is above the slag dischargeopening and protects the zone above the slag discharge opening againstradiation and also prevents an undesired radiation from the fire-box tothe contact heating surfaces.

It is an object of the present invention with boilers having asubstantially verticalflue, to provide an arrangement which in the fluewill produce an eflective turbulence of the flue gases burned already toa considerable extent.

It is another object of this invention to provide an arrangement as setforth in the preceding paragraph which will equalize the temperatureover the entire cross section of the flue.

These and other objects and advantages of the invention will appear moreclearly from the following specification in connection with theaccompanying drawings, in which:

FIG. 1 diagrammatically illustrates a steam producer with a verticalfire-box and a vertical flue adjacent thereto which in accordance withthe present invention is provided with a displacement body of anequilateral triangular shape.

FIG. la is a cutaway drawing along line Ia-Ia.

FIG. 2 is a diagrammatic representation of a steam producer according tothe invention similar to that of FIG. 1 but differing therefrom in thatthe displacement body has a diamond or rhombus shape. j

FIG. 2a is a cutaway drawing along line IIaIIa.

FIG. 3 illustrates the scheme of a steam producer according to thepresent invention.

The steam producer according to the present invention which has avertical fire-box and a vertical adjacent flue and, if desired, may beequipped with additional heating surfaces, is characterized primarly bya cooled displacement body above the fire-box.

This displacement body forces the combustion gases which rise in thecenter and the temperature of which is considerably higher than thetemperature of the combustion gases rising along the walls, to movetoward said walls. In this way, a considerable turbulence is producedwhich will bring about an intense intermixing of the flue gases ofdifferent temperatures thereby causing an equalization of thetemperature over the entire cross section of the flue. Normally, adisplacement body which is not suspended in the central zone wouldproduce a certain equalization of the temperature. However, the bestresult will be obtained when the displacement body is located in thecentral zone of the radiation flue.

' According to a further development of the present invention, thedisplacement body is suspended on supporting pipes so that it can movefreely and independently of the longitudinal extension of the wallpipes.

Since, in order to be effective, the displacement body must have acertain size, while on the other hand it is suspended on supportingpipes the number of which is to be restricted as far as possible, it isadvantageous for purposes o freducing the weight, to design thedisplacement body in the form of a hollow body. In this connection it isnot necessary that the displacement body is closed on all sides. Forproducing a turbulence, a displacement body open at the bottom andhaving a roof-shaped cross section has proved highly advantageous. Thiscross section may be supplemented by inclined plates arranged in theflue at a higher or lower level than the lower surface of thedisplacement body. When the displacement body is closed on all sides, itis advantageous to fill the same with light mate'rial, as for instancelight chamotte, in order, particularly when burning ash containingfuels, to prevent any collection of flue dust. The walls of thedisplacement body are at any rate formed by pipes through which acooling medium passes.

When the flue has a rectangular cross section which is in most instancesthe case when the boiler is fired from oppositely located sides, thedisplacement body advantageously extends from one side wall to anotherone. A construction is, of course, also possible according to which thedisplacement body is not directly connected to the side walls but leavesfree a flue gas passage so that elevated temperatures in the vicinity ofthe walls will be obtained. 7 q

With boilers having a considerable width, it may be advantageous insteadof one displacement body to employ a plurality of displacement bodieswhich are arranged in series one behind the other and thus supplementeach other over the entire width of the flue. The simpliest design willbe obtained by designing the displacement body in the form of a straightbeam and suspending the same horizontally in the flue. However, it isalso possible to design the beam so that it will have a slight V-shape,in other words, is somewhat inclined toward the outside.

The cross-sectional shape of the displacement body is advantageouslydesigned symmetrically. In this connection, the shape of an isosceles orof an equilateral triangle is advantageous which is vertical and thebasis of which faces the fire-box. It is also possible to design thedisplacement body with a diamond-shaped cross section and to suspend thesame in such a way that the lowermost point of the diamond is a tip.This shape makes it possible in a simple manner to provide a shroud orapron formed by evaporator pipes which are adjacent the lower end of thedisplacement body and if desired may extend close to the bottom. It is,of course, understood that also other cross-sectional shapes for thedisplacement body are possible, such as a cylindrical shape, withcircular as well as with elliptical cross-section, or a drop-shapedcross section.

When the flue has a circular cross section or the cross section of aregular polygon, the best flow conditions are obtained by designing thedisplacement body as a body of revolution and suspending saiddisplacement body at the longitudinal axis of the flue. In somecircumstances, a dis-placement body in the form of a disc will suflicethe plane of which is perpendicular to the longitudinal axis of the flueand which may have a circular cross section or a cross sectionconforming to the shape of the flue.

Referring now to the drawings in detail, the steam producer shown ineach of the various embodiments illustrated therein comprises a fire-box1, a radiation flue 2 and a flue 3 equipped with contact heatingsurfaces 13, 23. These three chambers are vertically one above theother. Fire-box 1 is at its front side provided with two rows of burners4, 14 and at its rear side with two rows of burners 5, 15. The burnerrows 4 and 5 are located opposite to each other and so are the burnerrows 14 and 15.

The contact heating surfaces 13, 23 arranged in flue 3 are formed bysuperheating pipes.

In conformity with the present invention, the radiation flue 2 which iscovered with evaporation pipes has a displacement body 8 suspendedtherein, said body 8 being supported by supporting pipes 9, 19, 29.

According to the arrangement shown in FIG. 1 and FIG. 1a, thedisplacement body has the shape of an equilateral triangle with thebasis thereof extending along asubstantially horizontal plane. When thefire gases of the intermediate layers rise, they are deviated toward theoutside as indicated by the arrows 10, 20. As a result thereof theyintermix with the outer flue gases and bring about an equalized oruniform temperature distribution in the cross section of the radiationflue above the displacement body 8.,

.The embodiment shown in FIG. 2 and FIG. 2a in which those parts whichcorrespond to the parts of FIG. 1 and FIG. la have been designated withthe same reference numerals as in the latter, differs from that of FIG.1 and FIG. 1a primarily in that the displacement body 8a instead ofbeing triangular has the shape of a diamond or rhombus. The displacementbody 8a is formed by a plurality of pipes 11 through which a coolingmediumis passed.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular arrangements shown in the drawings butalso comprises any modifications within the scope of the appendedclaims.

What I claim is:

1. In a steam producer, a vertical fire-box, rows of burners disposedalong opposite walls so that flue gases in the central space have highertemperatures than those at the sides of the fire-box, vertical fluemeans of the same substantially uniform cross section extendingvertically upwardly from said fire-box, including a first radiationsection having a clear central space surrounded by radiation absorbingsurfaces to extract heat by radiation, and a second section above ,saidfirst section through which the flue gases pass from said first section,contact heating surfaces disposed in said second section to extract heatfrom said gases by contact, and means to distribute the gases of unequaltemperatures equally through said second section comprising adisplacement body of substantial lateral extent suspended parallel tosaid opposite walls and extending substantially across the top centrallyof the first section immediately below the contact heating surfaces todeflect the hot gases of the central space toward the sides of the fluemeans to mix with the cooler gases along the sides.

2. A steam producer according to claim 1, in which said displacementbody is formed by pipes adapted to be connected to a source of coolingfluid.

3. A steam producer according to claim 1, in which said displacementbody has a symmetrical cross section in at least one vertical plane.

4. A steam producer according to claim 1, in which said displacementbody is formed by a continuous beam having a length approximatelycorresponding to the width of said radiation flue.

5. A steam producer according to claim 1, in which said displacementbody has an isosceles-shaped cross section with the plane thereofextending in the vertical direction of said flue means.

6. A steam producer according to claim 1, in which said displacementbody has the cross section of a diamond standing on one of its tips.

7. A steam producer according to claim 1, which includes supportingpipes extending longitudinally in said flue means and supporting saiddisplacement body.

8. A steam producer according to claim 1, which includes partition meansarranged in said flue means adjacent said displacement body means andformed by superimposed pipes adapted to be connected to a source ofcooling medium.

9. A steam producer according to claim 1, in which said displacementbody is formed by a plurality of pipe means adapted to be connected to asource of cooling fluid and defining the outer surface of said, body,said body being filled with light material.

10. A steam producer according to claim 1, in which said displacementbody is hollow, and which comprises reverse collector means arranged insaid displacement body.

References Cited UNITED STATES PATENTS 1,922,664 8/1933 Kerr 1222352,002,463 5/1935 Bailey et al. 122-235 2,672,849 3/1954 Fruit 122--3332,982,265 5/1961- Wedertz 122-235 3,003,480 10/ 1961 Fink et al 122-235FOREIGN PATENTS 806,997 1/ 1959 Great Britain. 1,194,599 5/ 1959 France.

KENNETH W. SPRAGUE, Primary Examiner,

1. IN A STEAM PRODUCER, A VERTICAL FIRE-BOX, ROWS OF BURNERS DISPOSEDALONG OPPOSITE WALLS SO THAT FLUE GASES IN THE CENTRAL SPACE HAVE HIGHERTEMPERATURES THAN THOSE AT THE SIDES OF THE FIRE-BOX, VERTICAL FLUEMEANS OF THE SAME SUBSTANTIALLY UNIFORM CROSS SECTION EXTENDINGVERTICALLY UPWARDLY FROM SAID FIRE-BOX, INCLUDING A FIRST RADIATIONSECTION HAVING A CLEAR CENTRAL SPACE SURROUNDED BY RADIATION ABSORBINGSURFACES TO EXTRACT HEAT BY RADIATION, AND A SECOND SECTION ABOVE SAIDFIRST SECTION THROUGH WHICH THE FLUE GASES PASS FROM SAID FIRST SECTION,CONTACT HEATING SURFACES DISPOSED IN SAID SECOND SECTION TO EXTRACT HEATFROM SAID GASES BY CONTACT, AND MEANS TO DISTRIBUTE THE GASES OF UNEQUALTEMPERATURES EQUALLY THROUGH SAID SECOND SECTION COMPRISING ADISPLACEMENT BODY OF SUBSTANTIAL LATERAL EXTENT SUSPENDED PARALLEL TOSAID OPPOSITE WALLS AND EXTENDING SUBSTANTIALLY ACROSS THE TOP CENTRALLYOF THE FIRST SECTION IMMEDIATELY BELOW THE CONTACT HEATING SURFACES TODEFLECT THE HOT GASES OF THE CENTRAL SPACE TOWARD THE SIDES OF THE FLUEMEANS TO MIX WITH THE COOLER GASES ALONG THE SIDES.